United Nations Secretary General Antonio Guterres has called for respect for the agreement between Israel and Hamas.
In a statement on Tuesday, after Israel launched fresh attacks on Gaza, Guterres said humanitarian support should be allowed into Gaza without any restrictions.
He insisted on the unconditional release of hostages.
“I am outraged by the Israeli airstrikes in Gaza,” the UN secretary General said.
“I strongly appeal for the ceasefire to be respected, for unimpeded humanitarian assistance to be re-established and for the remaining hostages to be released unconditionally."
His remarks followed the Israeli Defence Forces (IDF) fresh attacks on Monday.
According to the Hamas-run health ministry, more than 400 people have been killed by Israeli air strikes on Gaza.
The Israeli military said it was carrying out extensive strikes after talks to extend the ceasefire failed.
Israel Prime Minister Benjamin Netanyahu's office said they will "from now on act against Hamas with increasing military strength".
Israel accuses Hamas of repeated refusal to release its hostages and rejecting proposals to extend the ceasefire.
Israel adds that at least 59 hostages are still being held in Gaza, with up to 24 believed to be alive.
Hamas accuses Israel of attacking defenceless civilians, insisting that mediators should hold Israel "fully responsible" for violating and overturning the ceasefire.
The Hostages and Missing Families Forum has accused the Israeli government of deception by pulling out of a deal that could have brought everyone home.
The first phase of the ceasefire saw Hamas release 33 hostages in return for Israel releasing around 1,900 Palestinian prisoners and allowing aid and other goods to enter the Gaza Strip.
It ended on March 1, 2025.
The second phase of negotiations would include the release of all remaining hostages as well as a full withdrawal of Israeli forces from the Gaza Strip but negotiations collapsed.
